I am creating this as an issue because the vanilla Nether Brick texture was once lightened in MCPE for the same reason – it was too dark to see individual blocks with reasonable brightness settings. In my case, with app brightness maximized and device brightness set to automatic.

Dark Netherrack is even more dangerous than dark Nether Brick because players can easily fall through unseen gaps and be killed, either by falling damage, lava below or becoming stuck in combat. It rewards players for their purchases with death.